Lipid nanoparticles (LNP) are the most clinically advanced drug delivery systems, with seven LNP-based drugs having received regulatory approval. These approved drugs contain small molecules such as anticancer drugs and exhibit improved efficacy and/or reduced toxicity compared to the “free” drug. LNP carrier technology has also been applied to delivery of “genetic” drugs such as plasmids for expression of therapeutic proteins or small interfering RNA (siRNA) oligonucleotides (OGN) for silencing genes contributing to disease progression. Devising methods for efficient in vivo delivery of siRNA OGN and other genetic drugs is the major problem impeding the revolutionary potential of these agents as therapeutics.
Recent advances in LNP technology and the design of the cationic lipids required for encapsulation and delivery of genetic drugs highlight the potential of LNP systems to solve the in vivo delivery problem. LNP-siRNA systems have been shown to induce silencing of therapeutically relevant target genes in animal models, including non-human primates following intravenous (i.v.) injection and are currently under evaluation in several clinical trials.
A variety of methods have been developed to formulate LNP systems containing genetic drugs. These methods include mixing preformed LNP with OGN in the presence of ethanol or mixing lipid dissolved in ethanol with an aqueous media containing OGN and result in LNP with diameters of 100 nm or less and OGN encapsulation efficiencies of 65-95%. Both of these methods rely on the presence of cationic lipid to achieve encapsulation of OGN and poly(ethylene glycol) (PEG) lipids to inhibit aggregation and the formation of large structures. The properties of the LNP systems produced, including size and OGN encapsulation efficiency, are sensitive to a variety of formulation parameters such as ionic strength, lipid and ethanol concentration, pH, OGN concentration and mixing rates. In general, parameters such as the relative lipid and OGN concentrations at the time of mixing, as well as the mixing rates are difficult to control using current formulation procedures, resulting in variability in the characteristics of LNP produced, both within and between preparations.
Microfluidic devices provide an ability to controllably and rapidly mix fluids at the nanoliter scale with precise control over temperature, residence times, and solute concentrations. Controlled and rapid microfluidic mixing has been previously applied in the synthesis of inorganic nanoparticles and microparticles, and can outperform macroscale systems in large scale production of nanoparticles. Microfluidic two-phase droplet techniques have been applied to produce monodisperse polymeric microparticles for drug delivery or to produce large vesicles for the encapsulation of cells, proteins, or other biomolecules. The use of hydrodynamic flow focusing, a common microfluidic technique to provide rapid mixing of reagents, to create monodisperse liposomes of controlled size has been demonstrated. This technique has also proven useful in the production of polymeric nanoparticles where smaller, more monodisperse particles were obtained, with higher encapsulation of small molecules as compared to bulk production methods.
Despite advances in the development of methods for LNP systems containing genetic drugs, a need exist for devices and methods for preparing lipid nanoparticles containing therapeutic materials, as well as improved lipid nanoparticles containing therapeutic materials. The present invention seeks to fulfill this need and provides further related advantages.